WASHINGTON (AFP) - Washington aims to change Syrian President Bashar al-Assad's belief that he can hang onto power and accept "the inevitability" of his departure, Secretary of State John Kerry said on Tuesday.

"We need to address the question of President Assad's calculation currently," Mr Kerry told reporters. "I believe there are additional things that can be done to change his current perception." The new top US diplomat said he would not go into specifics in public, but has a "good sense" of possible proposals.

Speaking after talks with Jordanian Foreign Minister Nasser Judeh, Mr Kerry said he was convinced there was a certain "inevitability" given the current state of the conflict. "Now, that hasn't sunk into him yet, obviously," Mr Kerry added.

Although the top US diplomat has yet to outline the contours of his first foreign trip, he said one of his purposes was to "try to see what can be done with respect to that calculation and how we might be able to affect it." The United States is working for a negotiated solution to the 23-month conflict in which some 70,000 people are said to have died, Mr Kerry said.

The aim was to avoid "the implosion of the state, because that's dangerous for everybody, and it proposes the possibility of the worst kinds of outcomes." Mr Kerry hinted that the US and Jordan could take renewed steps to urge Russia, a key Syria ally, to bring more pressure to bear on Assad to quit.

Moscow has been sharply criticised for keeping up ties with the Assad regime as it battles opposition rebels, and for continuing arms sales to Damascus.

"I still remain hopeful that there may be an equation where the Russians and the United States could in fact find more common ground than we have found yet with respect to that," Mr Kerry said, adding that Jordan's King Abdullah II was expected to visit Moscow.

"The current situation is untenable," agreed Mr Judeh, saying there was general "agreement across the board" that political dialogue was needed.

"I think that rather than setting timelines, we have to start looking at ways and means of bridging respective positions so that we can arrive at a political dialogue taking place and resulting in what we all want, which is a transition and an end to this continuing violence," he added.

A top Russian diplomat said on Wednesday that Syrian Foreign Minister Walid al-Muallem and opposition National Coalition chief Ahmed Moaz al-Khatib would make separate visits to Moscow for talks in the coming weeks.